4-Piperidine acetamide compounds

ABSTRACT

New piperidine derivatives and in particular esters and amides of substituted (piperidinyl-4) acetic acid are used as stabilisers for polymers, especially for polyolefines.

United States Patent [191 Cook [ Dec. 30, 1975 [30] Foreign Application Priority Data July 28, 1972 United Kingdom 35488/72 [52] US. Cl. 260/293.63; 260/45.8 N; 260/247.5 B; 260/293.53; 260/293.64;

[51] Int. Cl. C07D 211/30 [58] Field of Search 260/293.63, 293.66, 293.64

[56] References Cited UNITED STATES PATENTS 3,498,992 3/1970 Kuhnis et a! 260/293.86 3,640,928 2/1972 Murayama et al 260/293.64 3,850,877 11/1974 Cook 260/293.63

OTHER PUBLICATIONS CA. 76: 14 299K (1972), Leukoeva et al.

Primary Examiner-Sherman D. Winters Attorney, Agent, or FirmNestor W. Shust [5 7] ABSTRACT New piperidine derivatives and in particular esters and amides of substituted (piperidinyl-4) acetic acid are used as stabilisers for polymers, especially for polyolefines.

6 Claims, No Drawings 4-PIPERIDINE ACETAMIDE COMPOUNDS In British Patent Specification No. 1,214,426 there is described the compound having the formula:

n co cu This compound is disclosed as a starting-material for the production of 2,2,6,6-tetramethyl quinuclidine which is said to be pharmacologically active.

A Russian publication Khim. Pharm. Zl-l, 1970, 4, (10), pages 16 to 21 describes compounds having the formula:

R cH COR H 0 3 a e 3 e11 wherein (a) R is CH and R" is OCl-l (b) R is C 14 and R" is OCH (c) R is C H and R" is NH or (d) R is hydrogen and R" is H c R, I

l 1 H H wherein R, and R are the same or different and each is a straightor branched alkyl residue having from 1 to 12 carbon atoms, or R, and R together with the carbon atom to which they are attached form a cycloalkyl group having from 5 to 12 carbon atoms; R, is hydrogen, a straightor branched alkyl residue having from 1 to 4 carbon atoms, an aralkyl residue having from 7 to 9 carbon atoms or a cycloalkyl group having 5 or 6 carbon atoms; R is a metal ion or a hydrocarbyl residue having from 2 to 20 carbon atoms and being either unsubstituted or substituted by halogen or interrupted by one or more oxygen or sulphur atoms; X is O, -S, or NR wherein R has the same significance as R and n is 2, 3 or 4; as well as salts of the amine function of the compounds of formula I.

When n is 2, R may be a divalent, straightor branched aliphatic residue (either saturated or unsaturated) having from 2 to 20 carbon atoms, a divalent alicyclic residue having from 5 to 20 carbon atoms, a divalent aralkyl residue having 8 to 20 carbon atoms, or a divalent aryl residue having 6 to 20 carbon atoms.

Examples of the group R when n is 2 are 1,2-ethylene, 1,2-propylene, 1,4-n-butylene, 1,3-n-butylene, l,6-n-hexylene, 1,7-n-heptylene, l,l0-n-decylene, 1,12-n-dodecylene, 2,2-dimethyl-1 ,3-propylene, 1,2,3- trimethyl-1,4-butylene, 3-thia-1 ,S-pentylene, 3-oxal,5-pentylene, 1,4-but-2-enylene, 1,4-but-2-ynylene, 2,5-hex-3-enylene, 1,2-cyclohexylene, 1,3-cyclohexylene, 1,4-cyclohexylene, hexahydro-p-xylylene, p-xylylene, m-xylylene, l,2-phenylene, 1,4-phenylene, 2,2- biphenylene, 4,4'-biphenylene, 2,6-naphthylene and 2,7-fluorenylene.

When n is 3, R may be a trivalent straightor branched chain aliphatic (either saturated or unsaturated) residue having 3 to 15 carbon atoms, a trivalent alicyclic residue having 5 to 15 carbon atoms, a trivalent aralkyl residue having from 9 to 15 carbon atoms, or a trivalent aryl residue having 6 to 16 carbon atoms.

Examples of the group R when n is 3 are 1,2,3- trisubstituted propane, 1,2,4-tri substituted butane, 2,5-dimethyl-l ,2,6-tri substituted hexane, 1,1,1- trimethylene-propane, 1,2,3-tri-substituted cyclohexane, 1,3,5-tri-substituted cyclohexane, 1,3,5-trimethylenebenzene and 1,2,7-trisubstituted anthracene.

When n is 4, R may be a straightor branched chain tetravalent aliphatic residue (either saturated or unsaturated) having 4 to 12 carbon atoms or a tetravalent alicyclic residue having from 5 to 12 carbon atoms, such as tetramethylenemethane or 1,1 ,4,4-tetramethylene cyclohexane.

When n is 2, 3 or 4 and R is an aliphatic or alicyclic residue each of these residues may be unsubstituted or substituted by halogen or interrupted by one or more oxygen or sulphur atoms or an aryl or aralkyl residue.

When R is a metal ion, it is preferably a transitional metal ion, more preferably an ion of a metal of Group VIII of the Periodic System of Elements and especially an ion of nickel.

Examples of the groups R, and R are methyl, ethyl, n-propyl, iospropyl, n-butyl, sec-butyl, n-hexyl, n-dodecyl, or together with the carbon to which they are bound R, and R can form a group such as: I

Particularly preferred substituents R and R are straight or branched alkyl groups having 1 to 4 carbon atoms and the most preferred value for each of R and R is methyl.

Examples of the groups R and R are hydrogen, methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, benzyl, a-methylbenzyl, a,p-dimethylbenzyl, cyclohexyl, cyclopentyl. Particularly preferred substituents R and R are hydrogen and alkyl having 1 to 4 carbon atoms and the most preferred is hydrogen.

Examples of salts of the compounds of formula I that can be used according to the invention include salts of an inorganic acid, such as phosphates, carbonates, sulphates, chlorides and the like, as well as organic acic salts such as acetates, stearates, maleates, citrates, tartrates, oxalates, benzoates and substituted carbamic acids.

Examples of the esters and amides of formula I are given in the following list:

l,2-ethylene-di[(2',2 ',6',6',-tetramethylpiperidinyl)- 4)acetate] 1,4-butylene-di](2',2',6',6',-tetramethylpiperidinyl- 4)acetate] l, l O-decylene-di](2',2',6',6',-tetramethylpiperidinyl-4 )acetate] 1 ,4-But-2-enylene](2,2,6,6-tetramethylpiperidinyl- 4') acetate] 3-thia-l ,5-pentylene-di[(2',2',6',6,-tetramethylpiperidinyl-4)acetate] piperidinyl-4') acetate l,4-butylene-di[ 2',2',6',6',tetramethylpiperidinyl- 4)thioacetate] 1,1 ,l -tris[(2',2',6',6'-tetramethylpiperidinyl- 4' )acetoxymethyl1-propane Tetrakis[(2',2',6',6,-tetramethylpiperidinyl- 4 )acetoxymethyll-methane 4' )acetyl]ethane-l ,Z-diamine.

4')acetyl]hexane-1,6-diamine.

]octane-1,8-diamine.

phenyl-l ,4-diamine.

l ,l ,4,4-tetrakis[(2',2',6,6',-tetramethylpiperidinyl- 4 )acetoxymethyl]-cyclohexane.

1 ,2-ethylene-di[2',2'-di-isopropyl-6,6-dimethylpiperidinyl-4'1-acetate N,N'-di[(2-ethyl-2'-n-propyl-6,6,-dimethylpiperidinyl-4')acetyl] butane-l ,4-diamine.

l,3-butylene-di[(2,2',6'6-tetramethylpiperidinyl- 4)acetate] 2,2,4-trimethylhexane-l ,6-di[2',2',6',6-tetramethylpiperidinyl-4' )acetate] 1 ,2-ethylene-di[a-methyl(2',2',6',6-tetramethylpiperidinyl-4 )acetate] N,N'-di[a-n-butyl(2',2',6',6'-tetramethylpiperidinyl- 4 )acetyl]-hexane-l ,6-diamine Bis[ (2 ,2 ,6 ,6-tetramethylpiperidinyl-4 )acetate Nickel II 3,5,S-trimethyl-l-[(2',2',6',6'-tetramethylpiperidinyl-4')]-3 [(2",2",6",6"-tetramethylpiperidinyl- 4 acetamidomethylene]cyclohexane 1, l 2-dodecylene-di[ 2,2 ',6 ',6'-tetramethylpiperidinyl-4') acetate] The present invention also provides a first preferred process in which a compound of formula I is produced comprising reacting a compound having the formula:

N K He 9.

wherein R R and R have their previous significance and R is hydrogen or an alkyl group having from 1 to 4 carbon atoms, with a compound having the formula:

R,(xl-l),, Ill wherein R,,, X and n have their previous significance,

The reaction may be conveniently effected with or without the use of a catalyst and a solvent. If a catalyst is used however, it may be a lithium amide, an alkali metal alkoxide, p-toluene sulphonic acid, calcium hydroxide, tetra-butyl titanate or di-butyl tin oxide. if a solvent is used, the solvent is one which is inert to the reactants and the reaction product. Suitable solvents include xylene, toluene, cyclohexane and dioxan.

The reaction is preferably carried out at an elevated temperature, for instance at a temperature within the range of from to 200C. Advantageously, the alcolhol R OH, which is produced during the reaction, is allowed to distil out of the reactor as it is formed.

if desired, the crude reaction product may be purifled, for instance by solvent extraction and by subsequent re-crystallisation from a suitable solvent, or by re-distillation.

The starting-material of formula II may be produced for example by hydrogenation of a compound having the formula:

0 C0. OR

H 0 I 0. H

wherein R R R and R have their previous significance.

In a second process, a compound of formula I is produced by hydrogenating a compound having the formula:

3, to X K V H c wherein R R R R X and n have their previous significance.

The hydrogenation of IV and V may be conveniently effected using molecular hydrogen or using chemical means such as lithium aluminium hydride. If molecular hydrogen is used, the hydrogenation may be conducted in known manner using a hydrogenation catalyst such as palladium, platinum, rhodium or nickel, preferably supported on a carrier such as silica, calcium carbonate or carbon. Advantageously the reaction is conducted at elevated temperature and pressure.

In a third, less preferred embodiment, a compound of formula I is produced by reacting a compound having the formula:

R -cH-Co wherein R R and R have their previous significance and Z is halogen, with a compound having the formula III as hereinbefore defined.

The reaction is conveniently effected in a solvent inert to the reactants and the reaction products. Suitable solvents include benzene, toluene, cyclohexane and dioxan. Advantageously the reaction is effected at an elevated temperature, preferably at the reflux temperature of the reaction mixture.

The starting-material of formula VI may be produced from the compound of formula II by methods wellknown per se.

Salts of the compounds of formula I may be prepared by the reaction of the free base with an organic or inorganic acid in a suitable solvent, e.g., benzene, ether or cyclohexane.

Metal salts of the compounds of formula I may be prepared by reaction of a compound having the formula:

R cH-{p A wherein R R and R have their previous significance and A is an alkali metal ion, preferably sodium, with a compound having the formula:

wherein M is a metal ion, preferably a transition metal ion, especially nickel, Z is halogen and n is 2, 3 or 4.

The reaction is conveniently effected in a solvent such as ethyl alcohol or water.

The present invention further provides a composition comprising an organic material, and, as stabiliser, a minor proportion of a compound of formula I as hereinbefore defined.

Compounds of formula I have been found to impart to polyolefines a high degree of stability towards deterioration normally induced by the effects of ultra-violet radiation or exposure to heat. Moreover, this improved stability is achieved without affecting the colour properties of the treated polyolefine. The stabilisers of the invention provide effective light and/or heat stabilisation especially for lowand high-density polyethylene and polypropylene and polystyrene as well as polymers of butene-l, pentene-l, 3-methylbutene-l, hexene-l, 4-methylpentene-l 4-methylhexene-l and 4,4-dimethylpentene-l and also coand ter-polymers of olefines, particularly of ethylene or propylene.

Other organic materials susceptible to degradation by the effects of light and the properties of which are improved by the incorporation therein of a compound of formula I include natural and synthetic polymeric materials, for instance natural and synthetic rubbers, the latter including, for example, homo-, coand terpolymers of acrylonitrile, butadiene and styrene.

Specific synthetic polymers include polyvinyl chloride and vinyl chloride co-polymers, polyvinyl acetate as well as condensation polymers derived from ether, ester (derived from carboxylic, sulphonic or carbonic acids) amide or urethane compounds; polyvinyl acetals; polyacrylates such as polymers and copolymers of methyl acrylate, ethyl acrylate, methyl methacrylate and ethyl methacrylate; polyamides; urea-formaldehyde and melamine-formaldehyde resins; cellulose plastics such as cellulose acetate, cellulose butyrate and cellulose nitrate. Certain of these polymers can, for instance, form the basis of surface coating media such as paints and lacquers having an oil or resin base, such as an alkyd or polyamide resin.

The amount of the compound of formula I which is incorporated into the organic material in order to achieve maximal protection against degradation by light varies according to the properties of the organic material treated and according to the severity of the light radiation and to the length of exposure. However, for most purposes it is sufficient to use an amount of the compound of formula I within the range of from 0.01% to by weight, more preferably within the range of from 0.1% to 2% by weight based on the weight of untreated organic material.

The compounds of formula I may be incorporated into the polymeric material by any of the known techniques for compounding additives with a polymer. For example, the compound of formula I and the polymer may be compounded in an internal mixer. Alternatively, the compound of formula I may be added as a solution or slurry in a suitable solvent or dispersant, for instance an inert organic solvent such as methanol ethanol or acetone to powdered polymer and the whole mixed intimately in a mixer; and the solvent subsequently removed. As a further alternative the compound of formula I may be added to the polymer during the preparation of the latter, for instance at the latex stage of polymer production, to provide pre-stabilised polymer material.

Optionally, the composition of the invention may contain one or more further additives, especially those used in polymer formulations, such as antioxidants of the phenol'or amine type, UV. absorbers and light protectants, phosphite stabilisers, peroxide decomposers, polyamide stabilisers, basic co-stabilisers, polyvinyl chloride stabilisers, nucleation agents, plasticizers, lubricants, emulsifiers, anti-static agents, flame-protectants, pigments, carbon black, asbestos, glass-fibres, kaolin and talc.

The present invention therefore includes binary, tertiary and multi-component compositions containing, as stabiliser, a compound of formula I together with one or more functional additives for polymers.

Examples of suitable antioxidants are those of the hindered phenol type such as those selected from the following groups:

1. Phenolic compounds having the general formula z)w l wherein Qis A is

-CR cooR") R is hydrogen or lower alkyl R is lower alkyl R" is alkyl group having from 6 14 carbon atoms w is an integer from 0 to 4. Illustrative examples of the compounds shown above are:

di-n-octadecyl-a-( 3 ,5 -di-t-butyl-4-hydroxy-benzyl) malonate di-n-octadecyl-a-(3-t-butyl-4-hydroxy-5-methyl-benzyl)malonate di-n-octadecyl-a,a'bis-(3-t-butyl-4- hydroxy-S-methyl-benzyl)malonate. 2. Phenolic compounds having the general formula Q-R"' Illustrative examples of the compounds shown above are:

2,6-di-t-butyl-p-cresol 2-methyl-4,6-di-t-butylphenol and the like 2,6-di-Octadecyl-p-cresol 3. Phenolic compounds having the formula Q w 2w Q Illustrative examples of the compounds shown are: 2,2'-methylene-bis(6-t-butyl-4-methylphenol) 2,2'-methylene-bis(6-t-butyl-4-ethylphenol) 4,4-butylidene-bis(2,6-di-t-butylphenol) 4,4-(2-butylidene)-bis(2-t-butyl-5-methylphenol) 2,2-methylene-bis[6-(2-t-methylcyclohexyl)-4- methylphenol] 2,2-methylene-bis(3-t-butyl-5-ethylphenol) 4,4'-methylene-bis( 3 ,S-di-t-butylphenol) 4,4-methylene-bis(3-t-butyl-5-methylphenol) 2,2-methylene-bis(3-t-butyl-5-methylphenol) the like. 4. Phenolic compounds having the formula:

ROQ Illustrative examples of such compounds are: 2,5 -di-t-butylhydroquinone 2,6-di-t-butylhydroquinone 2,5-di-t-butyl-4-hydroxyanisole 5. Ighenolic compounds having the formula:

S--Q. Illustrative examples of such compounds are: 4,4-thiobis-(2-t-butyl-S-methylphenol) 4,4'-thiobis-(2-t-butyl-6-methylphenol) 2,2'-thiobis-(6-t-butyl-4-methylphenol) 4,4'-thiobis-(2-methyl-5-t-butylphenol) 6. Phenolic compounds having the formula and Illustrative examples of such compounds are:

octadecyl-(3,5-dimethyl-4-hydroxybenzylthio)-acetate dodecyl-( 3 ,5 -di-t-butyl-4-hydroxybenzylthio )-propionate 7. Phenolic compounds having the formula wherein T is hydrogen R and Q as defined above.

Illustrative examples of such compounds are:

1 ,l ,3-tris( 3,5dimethyl-4-hydroxyphenyl-propane 1,1 ,3-tris(t-butyl-4hydroxy-2-methylphenyl)- butane l ,l ,5 ,5 tetrakis-( 3 '-t-butyl-4'-hydroxy-6'-methylphenyl)-n-pentane 8. Phenolic compounds having the formula:

B CH CH H B QCH C 2 3 CH CH B wherein B, B and B are hydrogen, methyl or Q, provided that when B and B are Q then B is hydrogen or methyl and when B is Q then B and B are hydrogen or methyl.

Illustrative examples of such compounds are:

l,4-di( 3 ,5di-t-butyl-4-hydroxybenzyl)-2,3 ,5,6-tetramethylbenzene l ,3,5-tri(3,5dit-butyl-4-hydroxybenzyl)-2,4,6-

trimethylbenzene 9. Phenolic compounds having the formula (Q) NH L D is alkyl group having from 6 l2 carbon atoms or I W a l Q-O N z wherein Z is O-Q, SD or S(C H )-SD. Illustrative examples of such compounds are: 2,3-bis-(3,5dit-butyl-4-hydroxyphenoxy)-6-(noctyIthio)-l ,3 ,5-triazine 2,4,6-tris-(4-hydroxy-3 ,5-di-t-butylphenoxy)- 1 ,3 ,5

triazine 6-(4-hydroxy-3,5-di-t-butylphenoxy)-2,4-bis-(noctylthioethylthio)-1,3,5-triazine 6-(4-hydroxy-3-methylphenoxy)-2,4-bis-(n-octylthio)-l ,3,5-triazine 6-(4-hydroxy-3t-butylphenoxy)-2,4-bis-(n-octylthioethylthio )-l ,3,5-triazine 6-(4-hydroxy-3methyl-S-t-butylphenoxy)-2,4-bis- (n-octylthio )-l ,3,5-triazine 2,4-bis-(4-hydroxy-3-methyl-5-t-butylphenoxy)-6- (n-octylthio)-l ,3,5-triazine 2,4,6-tris-(4-hydroxy-3methyl-S-t-butylphenoxy)- l ,3,5-triazine 6-(4-hydroxy-3,5-di-t-butylphenoxy)-2,4-bis-(noctylthiopropylthio )-l ,3 ,5-triazine 6-(4-hydroxy-3,5di-t-butylphenoxy)-2,4-bis-(ndodecylthioethylthio)-1 ,3 ,S-triazine 2,4-bis-(4-hydr0xy-3,5-di-t-butylphenoxy)-6'- butylthio- I ,3 ,S-triazine 2,4-bis-(4-hydroxy-3,S-di-t-butylphenoxy)-6-(noctadecylthio)- l ,3 ,S-triazine 2,4-bis-(4-hydroxy-3,5di-t-butylphenoxy)-6-(ndodecylthio)-1,3 ,S-triazine 2,4-bis-(4-hydroxy-3,5di-t-butylphenoxy)-6-(noctylthiopropylthio )-1 ,3 ,5-triazine 2,4-bis-(4-hydroxy-3,5di-t-butylphenoxy)-6-(noctylthioethylthio)-l ,3 ,S-triazine 2,4-bis-(4-hydroxy-3,5di-t-butylphenoxy)-6-(ndodecylthioethylthi0)-l ,3 ,S-triazine. ll. Phenolic compounds having the formula IQ zz zzl m wherein p is an integer from 2 to 4 and R' is a tetravalent radical selected from aliphatic hydrocarbons having from 1 to 30 carbon atoms, aliphatic monoand dithioethers having from 1 to 30 carbon atoms, aliphatic monoand diethers having from 1 to 30 carbon atoms and z is an integer from 0 to 6.

Illustrative examples of such compounds are Sub-class I n-Octadecyl-3-( 3 ,5di-t-butyl-4-hydroxyphenyl)-propionate n-Octadecyl-2-(3,5di-t-butyl-4hydroxyphenyl)-acetate n-Octadecyl-3 ,5 di-t-butyl-4-hydroxybenzoate n-Hexyl-3,5di t-butyl-4-hydroxyphenylbenzoate n-Dodecyl-3,5di-t-butyl4-hydroxyphenylbenzoate Neo-dodecyl-3-(3,5di-t-butyl-4-hydroxyphenyl)- propionate Dodecyl-B-( 3 ,5di-t-butyl-4-hydroxyphenyl )-propionate Ethyl-a-( 4-hydroxy-3 ,5 di-t-butylphenyl )-isobutyrate Ocatadecyl-a-( 4-hydroxy-3 ,5 -di-t-butylphenyl isobutyrate Octadecyl-a-(4-hydroxy-3,5-di-t-butylphenyl)-propionate 13 nol, benzoyl-resorcinol and 3,5-di-tert.butyl-4- hydroxybenzoic acid-2,4-di-tert.butyl phenyl ester and -octadecyl ester and -2-methyl-4,6-di-tert.butyl phenyl ester.

f. Acrylates, for instance a-Cyano-B,B-diphenylacrylic acid ethylor iso-octyl ester, a-carbomethoxy-cinnamic acid, methylor butyl ester and N-(B-carbomethoxy-vinyl)2-methyl indoline.

g. Nickel compounds such as nickel complexes of 2,2'-thiobis-(4-tert.octylphenol), for instance the 1:1 and 1:2 complexes, optionally having other ligands such as n-butylamine, triethanolamine or N-cyclohexyl-diethanol-amine; nickel complexes of bis-(4-tert.octylphenyl) sulphone such as the 2:1 complex, optionally having other ligands such as 2-ethylcaproic acid; nickel dibutyl dithiocarbamates', nickel salts of 4- hydroxy-3,5-di-tert. butylbenzyl-phosphonic acid mono-alkyl esters such as the methyl-, ethylor butyl esters; the nickel complex of 2-hydroxy-4-methyl-phenyl-undecylketonoxime; and nickel-3,5-di-tert.butyl-4- hydroxy benzoate, and

h. Oxalic acid diamides, for instance 4,4'-dioctyloxyoxanilide 2,2'-dioctyloxy-5,5-di-tert.butyl-oxanilide 2 ,2'-di-dodecyloxy-5 ,5 '-di-tert.butyl oxanilide 2- ethoxy-5-tertiarybutyl-2-ethyl-oxanilide 2-ethoxy-2'- ethyl-oxanilide mixtures of oand p-methoxy and ethoxy-di-substituted oxanilides and the compound of formula:

Phosphite stabilisers include triphenyl phosphite, diphenylalkyl phosphites, phenyl dialkyl phosphites, trinonylphenyl phosphite, trilauryl phosphite, trioctadecyl phosphite, 3,9-di-isodecyloxy-2,4,8,lO-tetraoxa-3,9-diphosphaspiro-(5,5)-undecane and tri-(4- hydroxy-3,5-di-tert.butylphenyl)phosphite.

Peroxide-decomposing compounds for polyolefins include esters of B-thiodipropionic acids, for instance the lauryl-, stearyl-, myristylor tridecyl esters, salts of mercaptobenzimidazoles such as the zinc salt and diphenylthiourea.

Suitable polyamide stabilisers include copper salts in combination with iodides and/or further phosphorus compounds and salts of bivalent manganese.

Basic co-stabilisers are, for example, polyvinylpyrrolidone, melamine, benzoguanamine, triallyl cyanurate, dicyandiamide, urea derivatives, hydrazine derivatives, amines, polyamides, polyurethanes, alkali and alkaline earth salts of higher saturated or unsaturated fatty acids such as calcium stearate.

Polyvinyl chloride stabilisers include organotin compounds, organo lead compounds and Ba/Cd salts of fatty acids.

Examples of nucleation agents are 4-tert.butyl benzoic acid, adipic acid and diphenylacetic acid.

As with the compound of formula 1, any further additive is advantageously employed in a proportion within the range of from 0.01% to 5% by weight, based on the weight of untreated organic materials.

Some Examples will now be given. Parts and percentages shown therein are by weight unless otherwise stated.

EXAMPLE 1 18.2 Parts by weight of ethyl (2,2,6,6-tetramethylpiperidinyl-4) acetate, 2.7 parts by weight of butane-l 4-diol and 1 part by weight of lithium amide, were heated at 160C/76O mmHg for 30 minutes and then at 160C/12 mmHg for a further 5 minutes. The resulting mass was cooled and treated with 200 parts by volume of water the resulting crystalline solid was filtered, dissolved in 30 parts by parts by volume of water. The solid was collected by filtration and dried at 60C/12 mmHg to give butylene-l ,4-di[(2,2,6,6'-tetramethylpiperidinyl-4')-acetate] melting at 30C. and having the following elemental analysis by weight:

17.2 Parts by weight of ethyl(2,2,6,6-tetramethylpiperidinyl-4) acetate, 1.4 parts by weight of pentaertythritol, and 1 part by weight of lithium amide were heated together with stirring at c/760 mmHg for 1 hour, then at 160C/12 mmHg for a further 1 hour. The resulting mass was cooled to room temperature, and poured into 100 parts by volume of water, this was then extracted with 4 X 50 parts by volume of ether. The combined ether extracts were dried over magnesium sulphate and the ether removed by distillation. The residual oil was dissolved in petroleum ether (boiling range 6080C.), decolourised with active carbon, and the petroleum ether was removed by distillation at 100C/12 mmHg, to give tetrakis [(2,2,6,6-tetramethylpiperidinyl-4)acetoxymethyl]methane, n 1.4653 having the following elemental analysis by weight:

18.2 Parts by weight of ethyl(2,2,6,6-tetramethylpiperidinyl-4) acetate, 3.5 parts by weight of 1,6- diamino hexane, and 3.6 parts by weight of sodium methoxide were heated at 160C/760 mmHg for 2 hours. The resulting mass was cooled and triturated with 100 parts by volume of petroleum ether (boiling range 6080C.) to give a white solid, this-was collected by filtration, placed in a soxhlet extraction funnel and continuously extracted with ethyl acetate (100 parts by volume). By filtration of the cooled ethyl acetate a white solid was obtained of pure N,N'-di [(2',2',- 6,6-tetramethylpiperidinyl-4 )'-acetyl] hexane-1,6-diamine (containing 1 molecule of ethylacetate entrained in the crystals) melting at 103C. and having the following elemental analysis by weight:

EXAMPLES 4 to s 38 parts of polypropylene were homogenised with 0.076 parts of n-octadecyl-B-(4'-hydroxy-3,5-t-butylphenyl) propionate in a kneading machine over a period of 3 minutes. 0.19 parts of the product of Example 1 was then added and homogenisation continued for another 7 minutes.

The homogenised mixture was removed from the kneader and pressed to a thickness of from 2 to 3 mm.

111 a press.

9 parts of the polypropylene mixture were then charged into a second press in which the press-plates were protected by aluminium foil having a thickness of 0.1 mm. The press was closed and, for 2 minutes, no pressure was applied. The pressure was then increased up to a maximum of 12 tons and this pressure held for 6 minutes, the temperature of the press being 260C. The pressure was released and the material (0.3 mm thick) was cooled under running water.

This material was cut into from 3 to pieces of 35 X 35 mm section and re-charged to the press. The press was closed and no pressure was applied for 2 minutes. Over another 2 minutes the pressure was increased to 8 tons, the press temperature being 260C. This pressure was maintained for 2 minutes and then the pressure released. The polypropylene foil of 0.1 mm thickness was removed and tempered immediately in a circulating air oven maintained at 150C over a period of 60 minutes.

A section measuring 44 X 100 mm was separated from the 0.1 mm tempered polypropylene foil and exposed to light irradiation in a fademeter device consisting of a circular bank of 28 alternating sunlight and blacklight lamps. The sunlight lamps were 2 feet long, 20-watt fluorescent lamps characterised by a peak emission of 3100 Angstrom units; the blacklight lamps were 2 feet long, 20 watt ultraviolet lamps characterised by a peak emission of 3500 Angstrom units. The sample was' rotated concentrically about the bank of lamps so that the radiation therefrom was uniformly distributed over the section under test.

The exposed sample was examined periodically, when portions of it were removed for tenicle testing and the time (T) required for the elongation of the sample to decrease to 50% of the initial elongation was determined.

The time (Tc) required for the elongation of a control sample (not containing the product of Example 1 to decrease to 50% of the initial elongation was then determined.

The performance of the compound of Example 1 as a light stabiliser could then be assessed by determining the factor T/Tc.

The results obtained including the use of other compounds of the invention as stabilisers are set out in the following Table:

TABLE-continued Additive Factor T (for compound) Tc (for control) Example Control 1 acetoxymethyl methane 6 N,N'-Bis(2,2,6,6-

tetramethyl piperidinyl-4 acetyl) Hexane 1,6-diamine 7 Ethane-l ,2-di[ 2 2,6',6'-tetramethylpiperidinylA') acetate tetramethyl piperidinyl-4') acetyl] ethane-1, Z-diamine EXAMPLE 9 C H N Found 68.05 10.76 13.13 Required for C, H., N O 68 .20 10.97 13.26

EXAMPLE 10 A mixture of 34 parts by weight of ethyl (2,2,6,6-tetramethylpiperidinyl-4) acetate, 3.1 parts by weight of ethanediol and 1 part by weight of lithium amide was heated with stirring from room temperature to 160C. over a period of 1 hour. The temperature was maintained at 160C. for a further 30 minutes during which time ethyl alcohol was allowed to distil from the reaction flask.

The resulting mixture was cooled to room temperature and poured into parts by volume of water, the water was extracted with diethyl ether (4 X 50 parts by volume). The combined ether extracts were dried over magnesium sulphate and the ether was removed by evaporation to give a colourless oil which was purified by distillation to give 1,2-ethylenedi[(2,2,6,6-tetramethylpiperidinyl-4) acetate] boiling at 188-90/0.3 mm. and having the following elemental analysis by weight:

EXAMPLE 1 1 A mixture of 13.8 parts by weight of ethyl (2,2,6,6- tetramethylpiperidinyl-4) acetate, 2.6 parts by weight of 2-butene-l-4-diol and 0.5 part by weight of lithium amide was heated at 160C. for 1 hour. Ethyl alcohol, produced during the reaction, was allowed to distil from the reaction flask during this time. The suspension was then cooled and poured into 100 parts by volume of water, the product was extracted with ether, the combined ether extracts were dried over magnesium sulphate and the ether removed by evaporation. Distillation of the residue gave pure l,4-but-2-en-di[(2',2,- 6',6'-tetramethylpiperidinyl-4')acetate], boiling at 2l0C./0.2m.m. and having the following elemental analysis by weight:

C H N Found 69.10 10.28 6.44% Required for 69.29 10.29 6.22% 2fi 4fi 2 4 EXAMPLE 12 C H N Found 72.03 11.31 4.72% Required for 72.29 11.42 4.96% 14 64 2 4 EXAMPLE 13 A mixture of 18.2 parts by weight of ethyl (2,2,6,6- tetramethylpiperidinyl-4) acetate, 4.2 parts by weight of diethyleneglycol and 0.5 part by weight of lithium amide was treated as in Example 1 l to give 3'-oxa-l '-pentylene di [(2,2,6,6-tetramethylpiperidinyl-4 )acetate], boiling at 206-208C./0.3 m.m. and having the following elemental analysis by weight:

C H N Found 66.60 10.53 5.68% Required for 66.63 10.32 5.98% C2GH1BN2O5 EXAMPLE 14 A solution of 2.4 parts by weight of nickel chloride hexahydrate in 40 parts by volume of methyl alcohol was added to a stirred solution of 4.4 parts by weight of sodium [(2,2,6,6-tetramethylpiperidinyl-4)acetate] (prepared by the hydrolysis of ethyl [2,2,6,6-tetramethylpiperidinyl] acetate in dilute sodium hydroxide) in 80 parts by volume of methyl alcohol at reflux temperature. The solution was heated at reflux for a further 4 hours, then cooled and the insoluble removed by filtration. Methyl alcohol was removed by distillation under reduced pressure and the green solid residue was extracted with 100 parts by volume of chloroform. A small amount of insoluble material was removed by 18 filtration and the solution was then evaporated to dryness to give a green solid nickel salt, having the follow ing elemental analysis by weight:

Carbon 44.05% Hydrogen 7.44% Nitrogen 4.80% Nickel 16.5 5%

I claim: 1. A compound of the formula wherein R and R are the same or different and each is a straightor branched alkyl residue having from 1 to 12 carbon atoms or R and R together with the carbon atom to which they are attached, form a cycloalkyl group having from 5 to 12 carbon atoms,

R and R is independently hydrogen, a straightor branched alkyl residue having from 1 to 4 carbon atoms, or aralkyl residue selected from benzyl, amethylbenzyl or 04-, p-dimethylbenzyl, or a cycloalkyl group having 5 or 6 carbon atoms,

R, is a divalent hydrocarbyl residue. having from 2 to 20 carbon atoms and being either unsubstituted or substituted by halogen or interrupted by one or more oxygen or sulphur atoms, or a salt of the amine function thereof.

2. A compound according to claim 1 wherein R and R are each methyl.

3. A compound according to claim 1 wherein R and R are each hydrogen.

4. A compound according to claim 1 wherein R is a divalent straight.- or branched aliphatic residue either saturated or unsaturated having from 2 to 20 carbon atoms, a divalent alicycllc residue having from 5 to 20 carbon atoms, a divalent aralkyl residue having from 8 to 20 carbon atoms or a divalent aryl residue having from 6 to 20 carbon atoms.

5. A compound according to claim 1 which is N,N'- bis-[(2,2,6,6'-tetramethyl-piperidinyl-4)-acetyl]- hexane-l ,6-diamine.

6. A compound according to claim 1 which is N,N'- bis-[(2', 2,6,6'-tetramethyl-piperidinyl-4')-acetyl]- ethane-1,2-diamine. 

1. A COMPOUND OF THE FORMULAA
 2. A compound according to claim 1 wherein R1 and R2 are each methyl.
 3. A compound according to claim 1 wherein R3 and R5 are each hydrogen.
 4. A compound according to claim 1 wherein R4 is a divalent straight- or branched aliphatic residue either saturated or unsaturated having from 2 to 20 carbon atoms, a divalent alicyclic residue having from 5 to 20 carbon atoms, a divalent aralkyl residue having from 8 to 20 carbon atoms or a divalent aryl residue having from 6 to 20 carbon atoms.
 5. A compound according to claim 1 which is N,N''-bis-((2'',2'' ,6'' ,6'' -tetramethyl-piperidinyl-4)-acetyl)-hexane-1,6-diamine.
 6. A compound according to claim 1 which is N,N''-bis-((2'',2'',6'', 6''-tetramethyl-piperidinyl-4'')-acetyl)-ethane-1,2-diamine. 